Variable pitch fan



Sept. 18, 1962 c. MARSICO 3,054,458

VARIABLE PITCH FAN Filed Aug. 17, 1959 F/5.5 /9 F/E.5

INVENTOR. 46 m rp'w 3,054,458 VARIABLE PITQH FAN Corrado Marsico, Via Quintino Sella 2, Milan, Italy Filed Aug. 17, 1959, Ser. No. 834,279 Claims priority, application Italy July 11, 1959 1 Claim. (Cl. 170-16045) Present invention refers to a control device of the air volume in cooling or ventilation plants and the like.

It is the object of this invention to obtain in the plants as mentioned above a quick and efficient temperature control through an alteration of the cooling gas flow. It is therefore possible for instance to maintain almost stationary the temperature even though there are sensible alterations in the plant that would aim at a noticeable temperature alteration. The use of a device according to the invention allows a very high saving (up to 50%) of the cooling energy, as the air amount supplied at any time to the plant is that one as strictly needed under determined operation conditions.

By an almost stationary temperature it causes less wear of the mechanical members in motion, by preventing in such a way a dangerous over heating or the like and obtaining a smaller consumption of lubricating means that is not overheated.

Further features of present invention will result from the following specification of the device, that is substantially characterized in that it comprises a blowing member with radial blades and associated with an operation means to alter the inclination angle of the blades as to the plane that is normal to the rotation axis, said means being on its turn controlled by a pressure fluid acting against a spring means so that an alteration of the blade angle and therefore of the cooling gas flow is caused by varying the fluid pressure.

The invention will be specified with reference to the accompanying diagrammatic drawing, being both description and drawing given as an indicative and not restrictive example of present invention.

FIGURES 1 and 2 show in a side view and a front view, respectively, a preferred embodiment of the device.

FIGURE 3 is a longitudinal axial section thereof.

FIG. 4 shows a front view of the device with removed cap.

FIG. 5 is a longitudinal axial section of a part of the main body and FIG. 6 is a side elevation of the push and rotation member.

With reference to the figures, A is the main body of the device, whose rotation about its axi is caused by known means which are not shown. Said body is provided with radial blades 1, that are equally spaced one another and each of which is fitted to a radial arranged pin 2, which is carried by the body A through bushes 3, 4 and the roller bearing 5.

In the inside seat 6 of body A bevel pinion 7 is keyed on each pin 2, being said bevel pinion engaged with two conical wheels 8, 8', that are coaxial one another and with the body rotation axis.

This body carries an inside axis bush 9, that is provided with a helical groove 10, with which engages a helical projection 11 of the push and rotation member 12, whose end leans against a deformable membrane cap 13, which is held at the end of body A by a fastening cap 14.

The bevel gear 8 has a bored hub 15 fixed thereto which is turnably mounted on th hollow shaft 22 and which extends with the free end thereof in the axial bore 16 of member 12 but cannot turn with bevel gear 8 relative to member 12 owing to a longitudinal key 17 between members 15 and 12.

A front fastening cap 18 of body A is secured through screws 19. A hollow shaft 22 has a threaded end portion and is fastened to said cap 18 by a nut 20 on a threaded end portion of shaft 22. The other end of shaft 22 projects through bevel gear 8' into the bore of hub 15 of bevel gear 8 and turnably supports both bevel gears 8 and 8.

The axial loads on the toothed wheels 7, 8, 8 are carried by roller bearings 23.

A helical spring 24 is arranged in the hollow shaft 22 and exerts an axial push on the member 12 in the direction of arrow X. The load of spring 24 can be regulated by acting upon the end threaded plug 25.

The flow of the pressure fluid through the inlet pipe 26 into the deformable membrane capsule 13 causes an axial motion of member 12 in a direction opposite to arrow X and against the action of spring 24.

The axial motion of said member 12 is converted into a rotation movement of this member about its axis since projection 11 slides in helical groove 10 of the stationary member 9, and is transmitted by means of key 17 to hub 15 of the bevel gear 8 and therefore to bevel pinions 7, by which, an alteration of the inclination of blades 1 and therefore of cooling gas flow is caused. A pressure increase of the operating fluid acting on the cap 13 causes a reduction of the blade inclination angle as to the plane that is normal to the rotation axis and therefore a flow reduction takes place. The pressure of the operating fluid is controlled to correspond to the desired cooling effect of the fan blades.

A very interesting application of the device according to the invention is as a fan for the radiator of an internalcombustion engine.

In a blade wheel with controllable pitch of the blade according to present invention an air delivery can take place that is strictly in conformity with the prevailing thermal conditions at any time. A considerable saving of energy therefore takes place and particularly at the engine start the running temperature is achieved quickly.

If the fluid pressure would become null for whatever reason (for instance owing to a pipe breaking), the cooling unit acts in such a way as to convey the maximum air amount (owing to the counteraction of spring 24) so that dangerous overheating is prevented.

The device according to the inventor can be actuated by the lubricating oil of the machine to be cooled.

The spring 24 acts as a damping member in such a way as to prevent a quick pressure alteration from exerting its action on the blade inclination, so that a smooth and gradual alteration thereof takes place.

The initial blade inclination is adjusted by the screws 27, which connect gear wheels 7 to the associated pin 2.

When the adjusted blades are the direction of the air flow can be changed without stopping or changing direction of rotation.

This invention may undergo in the practice changes and modifications which fall in the scope and spirit of the appended claim.

I claim:

A variable pitch fan comprising, in combination, an elongated supporting housing; a plurality of fan blades turnably mounted on said supporting housing for variation of the pitch angle thereof, each fan blade including a stud projecting into said housing; a bevel pinion fixed on each stud of said fan blades; a bevel gear meshing with said bevel pinions; a hollow shaft fixed to said housing and turnably supporting said bevel gear, said hollow shaft having an end portion extending outside one end of said housing; a member fixed in said housing and having a helical groove; a movable actuating member in form of a hollow piston and mounted in said housing for turning and axial movement and having projecting means engaging said helical groove so that axial movement of said actuating member effects turning movement thereof; means connecting said actuating member with said bevel gear for turning movement therewith while permitting axial movement of said actuating member relative to said bevel gear so that said actuating member during axial and turning movement thereof will turn said bevel gear Without'imparting an axial thrust thereto; a flexible membrance located at the other end of said housing, abutting said actuating member and forming in said housing a fluid tight pressure chamber having an inlet for an operating fluid so said fluid acting on said membrane is separated from said actuating member; spring means located partly in said hollow piston and partly in said hollow shaft for urging said actuating member against said membrane so that a presure increase of the fluid effects displacement of said membrane and of said actuating member against the action of said spring means and adjustment of the pitch angle of said blades and thereby a variation of the amount of air moved by said blades; and adjusting means mounted at said end portion of said 4 hollow shaft and acting on said spring means for adjusting the tension of the same.

References Cited in the file of this patent UNITED STATES PATENTS 606,322 Winand June 28, 1898 2,225,209 Dewey Dec. 17, 1940 2,316,940 Dewey et al Apr. 20, 1943 2,440,046 :Hautier Apr. 20, 1948 2,456,361 Atteslander Dec. 14, 1948 2,465,560 Warnke Mar. 29, 1949 FOREIGN PATENTS 550,882 France Dec. 22, 1922 887,484 France Aug. 16, 1943 942,363 France Sept. 13, 1948 964,695 France Feb. 1, 1950 461,562 Italy Jan. 31, 1951 

